Our work divides into six projects: 1. Structural Mechanics of the Lung - Theoretical and empirical study of the implications of static and dynamic non-homogeneities to the material properties of the lung. 2. Airway Aerodynamics - Testing in excised and in vivo preparations, a wave-speed theory of flow-limitation and further characterization of the frequency response characteristics of the respiratory system. 3. Chest Wall Mechanics and Mechanical Factors in the Control of Breathing - Now concentrating on studies in man and other mammals of diaphragmatic compensation for changes in operating length. 4. Comparative Mammalian Respiratory Mechanics - Describing and drawing inferences from animal models with different structure and functional requirements. 5. Development and Evaluation of Tests of Pulmonary Function - Further evaluation of flow-volume slope ratios as a measure of flow-volume configuration and the development of a more clinically useful body plethysmograph. 6. Development of Animal Equivalents to Clinical Asthma - Studies of prolonged asthmatic states induced in unanesthetized experimental animals.